# -*- coding: utf-8 -*-
from random import choice


class RandomWalk:
    """用于生成随机漫步的数据"""

    def __init__(self, number_points=5000):
        """初始化属性"""
        self.number_points = number_points
        # 起始于(0, 0)
        self.x_values = [0]
        self.y_values = [0]

    def fill_walk(self):
        """计算出number_points个点，添加到x_values和y_values中"""
        while len(self.x_values) < self.number_points:
            # 方向和位置都是随机选择的
            x_direction = choice([1, -1])
            x_distance = choice([0, 1, 2, 3, 4])
            x_step = x_direction * x_distance

            y_direction = choice([1, -1])
            y_distance = choice([0, 1, 2, 3, 4])
            y_step = y_direction * y_distance

            # 如果x_step和y_step都是0，说明在原地踏步，不允许
            if x_step == 0 and y_step == 0:
                continue

            # 计算出结果，加入到x_values和y_values
            next_x = self.x_values[-1] + x_step
            next_y = self.y_values[-1] + y_step

            self.x_values.append(next_x)
            self.y_values.append(next_y)
